Device for forming an end area of a workpiece

ABSTRACT

The invention relates to a device for forming an end area of a workpiece ( 2 ), especially for cold press-forming an end area of a pipe, comprising two force transmitting elements ( 7, 9 ) which are guided in a common housing ( 3 ). The device is characterised in that a first pressure chamber ( 26 ) is located between the two force transmission elements ( 7, 9 ) and in that a second pressure chamber ( 28 ) is allocated to the second force transmission element ( 9 ). When the first force transmission element ( 7 ) is in the bracing position, the second force transmission element ( 9 ) can be displaced in relation to the first force transmission element ( 7 ) in order to form the workpiece.

DESCRIPTION

[0001] The invention relates to a device for shape-forming the endregion of a workpiece, especially for cold-press shape-forming of a pipeend region. It is known to set in compression a workpiece by means of afirst hydro-dynamically actuable force transmission element and toshape-form the end region via direct or indirect application of forcethereagainst by a second hydrodynamically actuable force transmissionelement. The concept of hydro-dynamically actuable force transmissionelements comprehends a body which is actuable in a hydraulic and/orpneumatic manner. In connection with the highest force which is requiredfor the shape-forming of a workpiece, a hydraulic actuation is chosenspecifically for this purpose.

[0002] DE 195 11 447 A1 discloses a device adapted for shape-forming apipe end region. This device includes a recess for exchangeable jawsoperable to set the pipe in compression. By means of a firsthydraulically actuable piston, the jaws are driven under pressure inorder to compressively engage the pipe. The first piston comprises acentral through opening in which a piston rod of a second hydraulicallyactuable piston is guidably disposed. The two pistons are in this mannercoaxially movable within one and the same housing serially one behindthe other.

[0003] The piston rod of the second piston, which is provided with ashape-forming tool, can effect application of a force on the pipe endregion, in view of the fact that the piston rod extends through thecentral, end-to-end continuously open, opening in the first piston,whereby the pipe end region is shape-formed in the axial direction. Inthis manner, the end region deforms in correspondence with the geometryof the shape-forming tool and the jaws.

[0004] In a special configuration, the known device comprises athree-part housing. A first housing portion has a first bore in whichthe first, annularly shaped, piston is movably guided with its sleeveand has a second bore in which the second piston with its piston rod ismovably guided. The second bore has a relatively smaller diameter thanthe first bore. In this manner, a stop or shoulder for engaging thesleeve of the first, annularly shaped, piston is formed which definesthe maximum return position of the first piston. A hydraulic fluid canbe introduced for actuating the first piston between the stop orshoulder and the piston sleeve. A further portion of the three-piecehousing forms with the first housing portion a threadable housing endpiece which comprises a cylindrical bore for guiding the end piece ofthe second piston. The first housing portion forms a stop or shoulder inthe actuation direction of the second piston. A hydraulic medium can beintroduced between the stop or shoulder and the second piston in orderto effect a return movement of the second piston after the shape-formingof the pipe. The corresponding hydraulic space for receipt of thehydraulic fluid is sealed off relative to the first hydraulic spacebetween the sleeve of the first piston and its rearward stop orshoulder. The third portion of the three-piece housing forms thereceiving portion for the jaws and the forward portion of the first andthe second pistons or, respectively, the shape-forming tool. Theshape-forming tool is configured and connected with the forward endregion of the piston rod of the second piston such that, during returnmovement of the second piston, the first piston is correspondinglybrought along and the jaws are thus released from their compressionposition. In this connection, the central through opening of the firstpiston comprises a rearward stop or shoulder. The shape-forming processperformed by the known device disclosed in DE 195 11 447 A1 is, to thisextent, burdened with disadvantages in that a control of the course ofthe shape-forming process from the beginning to the end thereof as wellas a monitoring of the tool and the pipe to be shape-formed before thebeginning of the shape-forming process is neither provided for norpossible due to the coupling of the two pistons during their returnmovements.

[0005] The invention provides a solution to the challenge of makingavailable a device for shape-forming a workpiece end region which makespossible a better control of the shape-forming process.

[0006] The solution to this challenge is revealed in the advantageousembodiments and further configurations of the invention as set forth inthe patent claims which follow this description.

[0007] In this connection, the invention initially provides, in a firstembodiment, that, between the first force transmission element and thesecond force transmission element, a first pressure space is arrangedcommunicated with a first pressure connector and that the second forcetransmission element has a second pressure space, communicated with apressure connector, arranged relative thereto such that the introductionof a pressure medium into the second pressure space drives the secondforce transmission element in the compression and shape-formingdirection. During the forward displacement of the second forcetransmission element to set the workpiece in compression, the pressureexerted by the pressure medium in the first pressure space is maintainedvia blockage of the first pressure connector, whereby, upon reaching apredetermined overpressure, the pressure medium is released from thefirst pressure space, so that the second force transmission elementmoves relative to the first force transmission element, which remains inits workpiece compressive engagement position, to thereby effectshape-forming of the workpiece and, after the shape-forming of the endregion of the workpiece, the second force transmission element is movedrearwardly to its start position by a renewed introduction of a pressuremedium in the first pressure space and, by means of a special drive, thefirst force transmission element is moved correspondingly therewith backinto its start position.

[0008] In this connection, the advantage is provided that, by reason ofthe pressure controlled release of the pressure medium in the firstpressure space following the reaching of the overpressure during theforward displacement of the second force transmission element, theworkpiece compressive engagement pressure is uniformly maintained at therequired value. The required pressure need only be maintained so long asis necessary. In this manner, an unnecessarily high pressure, and anunnecessarily long time period for the maintained pressure and thetherewith connected unnecessary loss of performance and high temperaturedevelopment, are avoided in an advantageous manner. After completion ofthe shape-forming process, the second force transmission element ismovable in an active manner back into its start position.

[0009] In accordance with one embodiment of the invention, it isprovided that a third pressure space with a connection to a thirdpressure connector is provided as a drive for the return movement of thefirst force transmission element. Alternatively, the drive for thereturn movement of the first force transmission element can, however, beadditionally configured as a return spring.

[0010] In accordance with an embodiment of the invention, it is providedthat the start position of the first force transmission element isdefined between the housing and a first force transmission element stopor shoulder. By fixedly positioning the first force transmission elementin its start position as well as, also, by selection of the startposition of the second force transmission element, the relativedisplacement movement path between the second and the first forcetransmission elements required for the shape-forming process isconstructively laid out.

[0011] In accordance with embodiments of the invention, sensors areprovided which recognize the inserted workpiece as well as monitor therespective position of the first force transmission element to determinewhether the first force transmission element has again been returnedinto its start position. In this connection, it is provided, in acase-by-case manner, that before the start of the shape-forming process,it can be automatically determined whether a suitable compression and/orshape-forming tool is available and/or is properly positioned, wherebythe availability and/or the proper position of the shape-forming toolcan be determined by a non-contact distance measurement effected by asensor. Additionally, it can be provided that, via a sensor, the startposition of the shape-forming tool and the position thereof during theshape-forming process can be sensed.

[0012] In a further development of the inventive device, it can beprovided that the required relative movement path for the shape-formingprocess between the first force transmission element and the secondforce transmission element—that is, the so-called shape-form length L—isadjustably settable in a first process step, such that the first forcetransmission element is movable away from the second force transmissionelement by introduction of a pressure medium into the first pressurespace, whereby, via introduction of a pressure medium in the secondpressure space, the compression process and the shape-forming processfollow thereafter as described. A pressure medium is, accordingly,introduced into the first pressure space both for actuation of the firstforce transmission element as well as for releasing the second forcetransmission element, whereby there is obtained the advantage of a stillfurther improved control possibility for the shape-forming process.

[0013] In this connection, it can be provided that the length of thefirst pressure space between the first actuation surface and the secondactuation surface is adjustably set before the shape-forming of theworkpiece in order to set the desired defined work path. Followingtherefrom, the two force transmission elements can be moved whilemaintaining a constant relative position to one another until theworkpiece has been set in compression. As a further consequence thereof,the second force transmission element is movable precisely along thepredetermined length of the pressure space against the first forcetransmission element, so that the compressively engaged workpiece isshape-formed by a movement along this length. The shape-forming processis brought to an end in particular due to the engagement of the firstactuation surface and the second actuation surface of the first pressurespace with one another.

[0014] In a further configuration of the device, the length of thepressure space is directly or indirectly measurable in order toadjustably set the length. In particular, the length is indirectlymeasurable via a distance sensor which is oriented toward a surfacewhose distance from the distance sensor varies as a function of thelength of the pressure space. A surface of this type is, for example,configured as an outwardly expanding conical outer surface of the firstforce transmission element. It is advantageous if a non-contactmeasuring distance sensor is deployed.

[0015] A non-contact measuring sensor is provided which emits a signalin dependence upon whether the workpiece to be shape-formed is in astart position in which it can be compressively engaged and/orshape-formed. The sensor is, in particular, a distance sensor whichmeasures the distance in a measurement direction to the most closelyadjacent object. Such sensors, including, for example, a laser emittingsensor, are known.

[0016] In this event, the workpiece need only be disposed in the startposition in order to produce the signal. In particular for controllingthe compression process and/or the shape-forming process, a control isprovided which is connected via a signal connection with the sensor. Bymeans of the transmission of a signal to the control, especially, anautomatic signal, the compression process and/or shape-forming processis initiated.

[0017] In particular, non-contact measurement of a dimension of theworkpiece to be shape-formed or, respectively, a measurement value, isperformed which provides a clear measurement of the dimension of theworkpiece to be shape-formed. If, for example, a pipe is to beshape-formed, the possibility is available to measure the pipe diameter.This permits, before the start of the compression process and/or theshape-forming process, a monitoring of whether a workpiece with thedesired dimensions for shape-forming is standing ready. If the properworkpiece has not been brought into a start position or there is, in anyevent, no workpiece at all in the start position, a start signal iscorrespondingly also not produced. An unintended actuation of theshape-forming device or, respectively, the working of the workpiece withfalse dimensions can thus be avoided in this manner. An importantadvantage lies in the fact that security measures for protecting theoperating personnel can be maintained in a simple manner and, at thesame time, damage of the device such as through the disposition of toolarge a workpiece therein, can be prevented.

[0018] Furthermore, it is suggested that, before the start of thecompression process and/or the shape-forming process, that it beautomatically determined whether a suitable compression and/orshape-forming tool is available and/or is properly positioned. In thisconnection, it is particularly suggested to provide a non-contactmeasuring sensor which generates a signal as a function of whether asuitable compression and/or shape-forming tool is available and/or isproperly positioned. A shape-forming tool recognition in this manner canbe combined with the above-described sensor to produce a start signal inorder to achieve still greater assurance against false actuation andfalse functioning. In particular, the same sensor can be used formeasuring the start position and for measuring the availability and/orthe positioning of the shape-forming tool. In this event, theavailability and/or the proper positioning of the shape-forming tool is,preferably, initially measured or, respectively, pre-set.

[0019] Moreover, it is further suggested to provide a sensor whichmeasures in a non-contact manner the progression or continuing movementof the shape-forming of the workpiece. In particular, a control can befurther provided which receives a signal of the sensor, and which, afterthe shape-forming has been adequately performed, effects the end of theshape-forming process.

[0020] The inventive device is described hereinafter in connection withtwo embodiments thereof; in this regard, the drawings show:

[0021]FIG. 1 A longitudinal view through a shape-forming device in itsstart position,

[0022]FIG. 2 the shape-forming device shown in FIG. 1 having a workpiecereceived therein in the start position,

[0023]FIG. 3 the shape-forming device after the completion of theworkpiece compressive engagement process,

[0024]FIG. 4 the shape-forming device in its position at the end of theshape-forming process,

[0025]FIG. 5 the shape-forming device in the intermediate positionduring return movement at a time at which the second force transmittingelement has already been returned to its start position,

[0026]FIG. 6 the shape-forming device in another embodiment thereofcomprising a function for variable adjustment of the shape-form length(L), the shape-forming device being shown in the start position,

[0027]FIG. 7 the subject matter shown in FIG. 6 with an inserted pipeend,

[0028]FIG. 8 the shape-forming device as shown in FIG. 6 followingsetting of the shape-form length (L),

[0029]FIG. 9 the shape-forming device as shown in FIG. 8 upon reachingthe workpiece compressive engagement position of the first forcetransmitting element,

[0030]FIG. 10 the shape-forming device as shown in FIG. 9 followingcompletion of the shape-forming process.

[0031]FIG. 1 shows a longitudinal view through a shape-forming device 1.The shape-forming device 1 includes a base housing 3 having a centralcylindrical bore such that a cylinder surface 4 is formed thereby. Inthe region of the open end of the base housing 3, a receiving housing 5is disposed for receipt of jaws 31 operable as compression jaws. Thecylinder surface 4 is configured as a guide surface for guiding themovement of a first force transmission element configured as an outerring piston 7 and for guiding the movement of a second forcetransmission element configured as an inner piston 9. The inner piston 9substantially completely fills the closed end of the cylindrical bore. Apiston rod 11 of the inner piston 9 extends in the direction toward theopen end of the cylinder bore. The piston rod 11 is received in acentral cylindrical bore of the outer piston 7 and is fixedly coupledwith an extension piece 11(a) which is, in turn, connected to acompression tool 13. The outer piston 7 thus forms a guide for guidingthe movement of both the piston rod 11 and a rotation preventing device15 which connects the piston rod 11 or its extension piece 11(a) with acompression tool 13 operable as a shape-forming tool.

[0032] The rotation preventing device 15 is operable in a manner similarto a bayonet lock. A locking projection 16 of the compression tool 13 isdisposed, via a linear movement in the axial direction of the extensionpiece 11(a) of the piston rod 11, into a corresponding recess in theextension piece 11(a) and is thereafter pivoted about the longitudinalaxis of the piston rod 11 in order to lock the connection.

[0033] The base housing 3 comprises a first pressure connection 25through which a hydraulic medium can be introduced into the interior ofthe base housing 3 or, respectively, can be discharged from the basehousing 3. A first pressure space 26 in the base housing 3 iscommunicated with the first pressure connector 25, the pressure spacebeing disposed outside of the cylinder surface 4 and being limited, aswell, by a first actuation surface 10 of the outer piston 7 and by asecond actuation surface 12 of the inner piston 9. The first pressurespace 26 is configured as a relatively larger or smaller space as afunction of the operational condition of the shape-forming device 1 andcan be disposed in various positions relative to the first pressureconnector 25 (see FIGS. 1-5). In each operational condition, however,the first pressure connector 25 is communicated with the first pressurespace 26.

[0034] In particular, the first pressure space 26 expands outwardly inthe radial direction, as the first actuation surface 10 and the secondactuation surface 12 are each partially configured as conical surfaces.

[0035] As can be seen in FIGS. 3 and 4, the first actuation surface 10and the second actuation surface 12 each respectively comprise a furtherregion which is annularly shaped and represents a stop or shoulder forthe other piston 7, 9.

[0036] The first pressure space 26 is sealed off against the open endand the closed end of the cylinder bore of the base housing 3 by sealsbetween the piston rod 11 and the inner surface of the outer piston 7,by seals between the outer surface of the outer piston 7 and thecylinder surface 4, and as well by seals between the outer surface ofthe inner piston 9 and the cylinder surface 4. The seals arecollectively designated with the reference numeral 21.

[0037] In the region of the closed end of the cylinder bore, there isadditionally provided a second pressure space 28 in the base housing 3which is communicated with a second pressure connector 27. The secondpressure space 28 has a variable volume which can be varied to a valueof practically zero.

[0038] On the side of the outer piston 7 turned away from the firstpressure space 26, a third pressure space 51 is formed in thecompression and shape-forming device in front of the outer piston 7between this piston and a housing insert 52, the third pressure spacebeing communicated with a third pressure connector 50. This thirdpressure space 51 serves as a drive for the return movement of the outerpiston 7 into its start position.

[0039] The receiving housing 5 forms a receiving space for the jaws 31which are operable through actuation of the pistons 7,9—that is, throughthe movement of the pistons in the axial direction—to place a workpieceunder compression. The jaws 31 are, for example, configured and actuatedin the same manner as the jaws shown in DE 195 11 447 A1.

[0040] The jaws 31 include, on the right hand back end thereof as viewedin FIGS. 1-5, a shape-forming recess 33 which forms an encirclinggroove-type recess closing upon itself if a workpiece with acorresponding outer dimension is disposed under compression in theshape-forming device. The shape-forming recess 33 serves to shape-formthe workpiece as will be described hereinafter in more detail.Alternatively or additionally, the shape-forming can also be effected byselection of the geometry of an alternative compression tool which isprovided in lieu of the illustrated compression tool 13 and which isconnectable with the piston rod 11.

[0041] The compression tool 13 comprises, on its free back end at whichthe compression tool has a smaller outer diameter than the area thereofaxially behind this free back end, a measurement band 8.

[0042] The inner piston 9 comprises, in the region of the free end ofits piston rod 11 or its respective extension piece 11(a) which extendstoward the jaws 31, a conically shaped section 6 which forms the outerperiphery of the extension piece 11(a).

[0043] Two bores are formed in the complete housing formed by the basehousing 3 and the receiving housing 5, the two bores extending in aradial direction to the central longitudinal axis of the shape-formingdevice 1. A sensor S1 or, respectively, S2, is arranged in eachrespective bore. The sensor S1 serves to identify the compression tool13 in that the sensor S1 is oriented toward the measurement band 8 ofthe compression tool 13 and can identify the respective compression tool13 as a function of the distance between the sensor S1 and themeasurement band 8.

[0044] The sensor S2 serves to establish the base position of the innerpiston 9 in that the sensor S2 is oriented toward the conical surface 6of the extension piece 11(a) that is connected with the inner piston 9,so that, via the determination of the position of the conical surface 6or, respectively, the movement of the extension piece 11(a) with thecylindrical peripheral surface relative to the sensor S2, thecontinuation of the movement of the inner piston 9 is sensed.

[0045] An example of the operation of the shape-forming device 1 ishereinafter described:

[0046] Starting from the position of the shape-forming device as shownin FIG. 1, initially, a workpiece such as, in particular, the end of apipe 2, is introduced into the shape-forming device until the inward endof the pipe is seated against the compression tool 13, whereby the startposition of the shape-forming device can be seen in FIG. 2. As can beseen in FIG. 3, the pressure space 28 is filled with a pressurizedmedium which leads to a displacement of the inner piston 9 to the lefthand direction as seen in FIG. 3. Since the pressure connector 25 of thefirst pressure space 26 is closed during this first phase of thepressure filling of the second pressure space 28, the feeding force ofthe inner piston 9 is transmitted via the pressure medium present in thefirst pressure space 26 to the outer piston 7 so that this piston isdisplaced in the same direction in coordination with the displacement ofthe inner piston 9; with continuing movement of the two pistons 7, 9,the jaws 31 are pushed into position on the outer surface of the pipe 2and place the pipe in compression, whereby the outer piston 7 pushesoutwardly in a discharging manner the pressure medium present in thethird pressure space 51. Once the pipe 2 is placed in compression, theouter piston 7 can no longer be further moved and, in this manner, thepressure rises in the pressure medium in the first pressure space 26until an overpressure corresponding to the desired compression force isreached. Upon reaching the overpressure, the pressure connector 25 isopened so that the pressure medium in the first pressure space 26 canflow out of the pressure space. In this manner, a continuation of thefeed movement of the inner piston 9 is made possible, with the pistonnow being further displaced relative to the fixedly positioned outerpiston 7 and thereby performing a compression working until the spacebetween the annular surfaces of the inner pistons 9 and the outer piston7, which has been laid out as a function of the compression work to beexerted, has been exhausted.

[0047] Upon the completion of the compression working, the pressureconnector 27 of the second pressure space 25 is moved into a releaseposition and a pressure medium is introduced via the first pressureconnector 25 into the first pressure space 26; in this manner, the innerpiston 9 is moved in the right hand direction into its start position,as can been seen in FIG. 5. Thereafter, a pressure medium is introducedvia the third pressure connector 50 into the third pressure space 51and, thereby, the outer piston 7 is likewise moved in the right handdirection into its start position as can be seen in FIG. 1, orrespectively, in FIG. 2. The end position of the outer piston 7 isthereby determined or given by a stop member (not shown) between theouter piston 7 and the housing.

[0048] With respect to the embodiment of the shape-forming device shownin FIGS. 6-10, there is performed, in addition to the functionsperformed by the embodiment described in accordance with FIGS. 1-5, anadditional function by which the shape-form length L required for theworking of the workpiece is variably adjustable in a first functionalstep. Otherwise, the same components are designated with the samereference numerals.

[0049] Thus, a receiving space 18 extends outwardly from the rotationpreventing device 15 in the axial direction of the piston rod 11 towardthe interior thereof, a compression spring 17 being received in thereceiving space. The compression spring presses the compression tool 13into a position in which a gap is created between the compression tool13 and a surface 14 formed on the back end of the piston rod 11.Correspondingly, a gap is also formed in the region of the rotationpreventing device 15 between the compression tool 13 and the piston rod11 which permits movement of the compression tool 13 against the pistonrod 11 by the width of the gap.

[0050] In addition to the seals 21 disposed between the respectivemoveable components, guide rings 19 are provided for guiding themovement of the pistons 7, 9.

[0051] Moreover, a sensor arrangement is variably configured in theembodiment shown in FIGS. 6-10. In this connection, the jaws 31 includea measurement groove 35 which extends radially inwardly from the outersurface of the jaws 31. In lieu of the measurement groove 35, ameasurement indentation can be provided which, unlike the groove shownin FIGS. 6-9, does not extend in the circumferential direction aroundthe jaws 31 but is, however, only a single indentation formed in onelocation or at several locations on the jaws. In this event, the properpositioning must be observed relative to a distance sensor, whosefunction is described in more detail hereinafter.

[0052] The jaws 31 further include a measurement opening 29 extending inthe radial direction which permits an electromagnet emission such as, inparticular, a laser emission, to be directed from outside the jaws 31interiorly onto a workpiece which is held in compression by theshape-forming device. The measurement opening 29 terminates on theinside of the shape-forming recess 33 so that, as will be described inmore detail hereinafter, the progress of the shape-forming process canbe measured.

[0053] In a variation of the embodiment shown in FIGS. 1-5, the conicalsurface 6 is configured on the free end of the outer piston 7 turnedtoward the jaws 31, whereby the conical surface 6 defines the outerperiphery of the outer piston 7.

[0054] In addition to the bores previously described with respect to theembodiment in FIGS. 1-5 for receipt of the sensors, both bores in theembodiment shown in FIGS. 6-10 each comprise a distance sensor 37, 39.The distance sensors 37, 39 measure the distance to the most closelyadjacent object lying in the radial direction inwardly or, respectively,the distance to the oversurface associated therewith. As schematicallyshown in FIG. 6, the first distance sensor is connected via a firstsignal lead 43 with a control 41. Furthermore, the second distancesensor 39 is connected via a second signal lead 45 with the control 41.The control 41 is, in turn, connected with a display device 47 whichcomprises six light emitting diodes 49. The light emitting diodes 49serve to display the operational phases and the measured operationalconditions of the shape-forming device 1.

[0055] By use of the device shown in FIGS. 6-10, the device measures thefirst distance via the first distance sensor 37 to the measurement band8 of the compression tool 13. The outer diameter at the measurement band8 is a characteristic measure of the type of compression tool that thecompression tool 13 is, especially with respect to its othermeasurements. Each compression tool connectable with the piston rod 11or any other tool has, in any event, a measurement band which, however,has a different outer diameter. In accordance with the distance to themeasurement band 8 and, correspondingly, the outer diameter of thecompression tool 13, the first distance sensor generates a measurementsignal which is transmitted to the control 41. The control 41 which is,in particular, configured as an intelligent microprocessor-configuredcontrol, recognizes the presence of the tool via the measurement signal.

[0056] The second distance sensor 39 measures the distance to the bottomof the measurement groove 35 in the jaws 31. The distance to the groovebottom is a representative measure of the type of jaws which the jaws 31are. The second distance sensor 39 generates a corresponding measurementsignal via the second signal lead 45 to the control 41. The control 41recognizes the jaws 31.

[0057] The jaws 31 and the compression tool 13 serve to shape-form acertain type of pipe—namely, the shape-forming of pipes with apredetermined outer diameter. From the information concerning whichcompression tool and which jaws are available, the control 41 determineswhat type of pipes can be shape-formed in combination with theworkpieces.

[0058] As shown in FIG. 7, if a pipe is received in a receiving opening20 of the compression tool 13 and, as shown by the arrow pointing to theright, is impacted by a force, the shape-forming of the pipe 2commences. If the force is sufficiently large in order to move thecompression tool 13 so as to overcome the counter force of the spring 17against the rod rear surface 14, then the compression tool 13 ispositioned at a spacing from the jaws 31. As a result of this, the firstdistance sensor 37 can now measure the distance or spacing to the outersurface of the pipe 2. The first distance sensor 37 transmits via thefirst signal lead 43 a corresponding measurement signal to the control41. The control 41 monitors whether the pipe 2 has the proper outerdiameter or, respectively, whether the proper measurement signal wasreceived. If this is the case, the control 41 starts the compression-andshape-forming process.

[0059] In this connection, as can be seen in FIG. 8, the outer piston 7is initially moved along the shape-form length L in the axial direction(in the illustration in FIG. 8, towards the left). In order to ensurethat the movement is accomplished, a hydraulic medium is introducedthrough the first pressure connector 25 into the first pressure space26. During this procedure, the first distance sensor 37 measures thedistance to the conical surface 6 of the outer piston 7 and continuouslytransmits a measurement signal to the control 41. Once the distancebetween the annularly-shaped surfaces of the first actuation surface 10and the second actuation surface 12 is the same as the shape-form lengthL, and the first distance sensor 37 has transmitted a correspondingmeasurement signal to the control 41, the control 41 interrupts theintroduction of the hydraulic medium into the first pressure space 26 sothat the movement of the outer piston 7 is stopped.

[0060] Thereafter, as best seen in FIGS. 9 and 10, the actualcompression and shape-forming of the pipe 2 begins, as has beenbasically described with respect to the embodiment shown in FIGS. 1-5,whereby the control 41 commences the introduction of a hydraulic mediumthrough the second pressure connector 27 into the second pressure space28. Following this operational condition, which is shown in FIG. 9, thecompression-and shape-forming work is completed as has already beendescribed with respect to the embodiment shown in FIGS. 1-5.

[0061] Insofar as the compression work of the jaws 31 is effected in arapid manner, the continuing movement of the inner piston 9 in the axialdirection towards the left ensures that no slippage of the pipe 2through the jaws 31 occurs, once the inner piston 9 has reached itsmaximal extended position. If, for example, because of relatively lowsurface roughness of the pipe outer surface and/or the jaws 31, aslippage of this type should occur, an adjustment of the distancebetween the actuation surfaces 10, 12 (see the operational phase shownin FIG. 8) can be implemented. In this event, the shape-form length Ldoes not, in fact, exactly correspond to the actual path, in which theend of the pipe 2 is shape-formed in the axial direction. A precisepre-adjustment of the desired shape-form path is, however, possible. Afurther factor, which can lead to inequality between the shape-formlength L and the actual shape-form path, is the yieldability or,respectively, the elasticity, of the material connection between theouter piston 7 and the jaws 31. In particular, elastic material can bedeployed such as, for example, a material to effect a damping of noiseor to prevent a wearing away.

[0062] As the end region of the pipe 2 is shape-formed via theapplication of force by the shape-form tool 13 in the axial direction,the second distance sensor 39 measures, through the measurement opening29, the distance to the bend or bulge 36 formed as a result of theshape-forming around the outer periphery of the pipe 2. A correspondingsignal is continuously provided by the second distance sensor via thesecond signal lead 45 to the control 41. After the shape-forming of thepipe has ended by means of engagement of the shape-form tool 13 againstthe jaws 31, the actual measurement value is compared with a desiredvalue and it is determined whether the bulge 36 has achieved the desiredouter diameter. Alternatively, the shape-forming can be ended once thecontrol 41 determines that the bulge 36 has achieved the desired outerdiameter and the control can thereby interrupt the shape-formingprocess. In this event, the shape-form length L serves to ensure that asufficiently long shape-forming path is available.

[0063] After the stroke movement of the inner piston 9 in the axialdirection to the left has ended, the second pressure space 28 isreleased from its pressurized condition—that is, the hydraulic mediumdisposed therein is permitted to flow out through the second pressureconnector 27. Moreover, the pressure medium in the first pressure space26 is flowed out via the first pressure connector 25. In this manner,the inner piston 9 is moved under the influence of the pressure mediumin the second pressure space 25 in the axial direction toward the right.Thereafter, via opening of the blocking valve, the hydraulic medium inthe first pressure space 26 is released so that the hydraulic mediumflows out of the pressure space 26. The outer piston 7 is returned toits start position by means of spring force generated thereagainst byone or more not-illustrated springs to return to its start position asshown in FIG. 6. In this manner, the jaws 31 release the shape-formedpipe 2 so that this pipe can be removed.

[0064] Once the heretofore described work steps, operational conditionsand/or operational phases have been successfully concluded, therespective status is indicated by illumination of a respective one ofthe light emitting diodes 49. In this connection, the control 41controls the display device 47. The meaning of the illumination of thein total six light emitting diodes 49 is, in connection with the serialpassage of a successfully concluded shape-forming process, as follows:

[0065] 1. Light Emitting Diode: Compressive- and shape-forming toolcorrectly disposed,

[0066] 2. Light Emitting Diode: Pipe outer diameter is appropriate forthe shape-forming tool,

[0067] 3. Light Emitting Diode: Forward movement of the outer piston andsetting of the shape-forming length L concluded,

[0068] 4. Light Emitting Diode: Pipe set in compression,

[0069] 5. Light Emitting Diode: Pipe is shape-formed, shape-formingresult is satisfactory,

[0070] 6. Light Emitting Diode: Return stroke is concluded, pipe can beremoved.

[0071] If a mistake occurs, this can be determined by reading thedisplay device 47, which indicates the respective operational phase or,respectively, operational condition, during which the mistake occurred.In particular, an additional, not-illustrated light emitting diode canbe provided which displays or illuminates if there is an interruption ofthe shape-forming process. Alternatively or additionally, a mistake canbe indicated by intermittent lighting of a light emitting diode to showthe corresponding operational phase. Also, it can be additionallyinterpreted that, if, for example, a light emitting diode does notilluminate, yet a light emitting diode later in the series doesilluminate, that a mistake has occurred.

1. A device for shape-forming an end region of a workpiece (2),especially for cold-press shape-forming of a pipe end region, whereby afirst hydro-dynamically actuable force transmission element (7) forsetting in compression a workpiece (2) and a second hydro-dynamicallyactuable force transmission element (9), whose force transmissioneffects the shape-forming, are provided, and the force transmissionelements (7,9) are coaxially guidably moved and are disposed in one andthe same housing (3), characterized in that, between the first forcetransmission element (7) and the second transmission element (9), afirst pressure space (26) communicated with a first pressure connector(25) is disposed, a second pressure space (28) connected with a secondpressure connector (27) is disposed relative to the second forcetransmission element (9) such that the introduction of a pressure mediumtherein moves the second force transmission element (9) against thecompression- and shape-forming device, whereby, during the forwarddisplacement of the second force transmission element (9) to set incompression the workpiece (2), the pressure in the pressure mediumenclosed in the first pressure space (26) is maintained, via blockage ofthe first pressure connector (25), and, upon reaching a predeterminedoverpressure, the pressure medium is released from the first pressurespace (26), so that the second force transmission element (9) is movablerelative to the first force transmission element (7), which itselfremains in the workpiece compressive engagement position, to therebyeffect shape-forming of the workpiece, and after the shape-forming ofthe end region of the workpiece (2), the second force transmissionelement (9) and, eventually, by means of a special drive (50,51), thefirst force transmission element (7) as well, are moved back into theirstart positions by renewed introduction of a pressure medium into thefirst pressure space (26).
 2. A device according to claim 1,characterized in that, a third pressure space (51) having a connectionto a third pressure connector (50) is provided as the drive for thereturn movement of the first force transmission element (7).
 3. A deviceaccording to claim 1, characterized in that, a return spring is providedas a drive for the return movement of the first force transmissionelement (7).
 4. A device according to one of claims 1-3, characterizedin that, the start position of the first force transmission element (7)is defined by a stop or shoulder configured between the housing (3) andthe first force transmission element (7).
 5. A device according to oneof claims 1-4, characterized in that, before the start of thecompression-and/or shape-forming process, it can be automaticallydetermined if a suitable compression-and/or shape-forming tool (13,31)is available and/or is properly positioned.
 6. A device according toclaim 5, characterized in that, the availability and/or the properposition of the workpiece (13,31) can be determined via a non-contactdistance measurement effected by means of a sensor S1.
 7. A deviceaccording to one of claims 1-6, characterized in that, the base positionof the shape-forming workpiece (13,31), and its position during theshape-forming process as it moves along the work path, are detectable bya sensor S2.
 8. A device according to one of claims 1-7, characterizedin that, to effect variable adjustment of a working path (shape-formlength L) provided for the shape-forming of the workpiece (2), the firstforce transmission element (7) is, before the beginning of thecompression-and shape-forming process, movable away from the fixedlypositioned second force transmission element (9) via introduction of apressure medium into the first pressure space (26).
 9. A deviceaccording to claim 8, characterized in that, the length of the firstpressure space (26) is adjustable between the first actuation surface(10) and the second actuation surface (12) before the shape-forming ofthe workpiece (2) in order to set a defined work path.
 10. A deviceaccording to claim 9, characterized in that, the length of the firstpressure space (26) is directly or indirectly measurable in order toadjustably set the length thereof at a desired value.
 11. A deviceaccording to claim 10, characterized in that, the length is indirectlymeasurable via a distance sensor (37), which is oriented toward asurface (6), whose distance from the distance sensor (37) varies as afunction of the length of the pressure space (26).
 12. A deviceaccording to one of claims 8-11, characterized in that, non-contactmeasurement can be performed to determine whether the workpiece to beshape-formed is in a start position, has been placed in compression,and/or has already been subjected to the start of the shape-forming, anda signal can be generated as a function of the measurement result.
 13. Adevice according to claim 12, characterized in that, a distance to theworkpiece (2) to be shape-formed is measurable via a non-contactmeasurement.
 14. A device according to one of claims 8-12, characterizedin that, the availability and/or the proper position of the compressiontool (13) is determinable via the same sensor (37) which also measuresthe start position of the workpiece (2) and, thereby, the measurement ofthe start position can be cleared once the workpiece (2) has beenbrought into the start position.